Dental burr and hand-piece assembly



Feb 9, 1943. M. M. ELLMAN DENTAL BURR AND HAND-PIECE ASSEMBLY Filed May 7, v1941 WEEE... .4

Patented Feb. 9, 1943 Unire stares orrics 2,310,409 DENTAL BURR AND HAND-PIECE ASSEMBLY Martin ll/. Ellman, Rockford, Ill. Application May 7, 1941, Serial No. 392,208 2 Claims. (Cl. 355-58) This invention relates to dental burrs or burr practice, the heating of the contra-angle handand dental hand piece assemblies equipped with piece will add to the temperature of the burr.

vibration dampener inserts to reduce shock or It is then an object of this invention to provibration, noise, and heating of the tooth or vide means for reducing shock, vibration, and

other material acted on by the burr. y 5 heating of a tooth during a drilling operation.

Specically the invention relates to the inter- A further object of this invention is to proposing of a non-metallic vibration dampener vide vibration dampener inserts between the insert between a dental burr and the chuck of head of a dental burr and the dental unit drivthe dental handpiece. ing the burr.

In the following description the term burr A specific object of this invention is to prowill cover dental drills, oral surgery burrs and vide dental burrs with non-metallic vibration dental mandrils for the mounting of various dampening material to absorb vibratory action dental stones or disks useful in grinding and of the burr head in operation. polishing. Another object of the invention is to reduce Shock, vibration and noise in the drilling Gr.15 the shock or vibration of 4dental burrs by cova tooth originate in the cutting portion of a ering the shanks thereof'with` non-metallic viburr when it is in operation and held against the bration dampener material such as rubber, plastooth. This vibratory action and uncomfortable tC,W00d 0r the like, or with soft metal dampfeeling is caused by the impact of the numerous ener material such as lead. serrated or convex surfaces of the burr as they A specific object of the invention is to prorotate against the tooth. Heretofore these vi- Vide a dental burr with a Vibration dampenins brations were transmitted successively throughV Sleeve around the Shank thereof.

the centra-angle piece if one were used, the Another specic object of the invention is to straight handpiece, and nally the long arm of line the chuck of a dental handpiece with vibrathe dental unit. As a result, the vibrating surtion dampening material.

faces were considerably increased, thereby pro- Other and further Objects of the invention ringing a, large vibrating mass will be apparent to those skilled in the art from The large vibrating mass increases the impact the fOllOWDg detailed deSCriPtOn Of the arlshock against the tooth causing discomfort to neXed Sheet 0f drawings Which', by Way 0f examthe patient. Since a large mass is caused to C ple, illustrates preferred embodiments of the ir1- vibrate the noise of vibration is increased, add- Vention. t will be understood,- however, that ing to the nervous strain of the patient. the invention is not limited to illustrated pre- In accordance with the present invention, a ferred embOdmentS- non-metallic vibration dampener insert is inter- On the drawing: posed between the dental burr and the dental 35 Figure 1 iS en eleVetOnel View 0f a dental burr unit, such as the contra-ange handpiece or the according t0 this invention especially adapted straight handpiece. This insert absorbs the for use in Contra-angle handpeeesvibration, and as a result the vibrating surface Figure 2 is a Cross-Sectional VeW, With perl5 is considerably reduced because a major portion in elevation, taken along the line II-II of Figure of the vibration cannot lter past the insert. `i0 1 According to this invention either the shank Figur-e 3 is an elevational view of another forni of the dental burr or the chuck of the handpiece of dental burr according to'this invention especan be covered with the vibration dampener ma- Cially adapted fer use irl Central-allele handterial. Non-metallic substances such as rubber, pieces. y

Bakelite, acrylic resins and other plastics, wood, Figure 4 is a cross-sectional View, with parts or the like, are satisfactory. These materials, in elevation, taken along the line IV-IV of Figure because of their relative elasticity, iilter out 3. Y

the transmission of vibration to the handpiece, Figure 5 is a broken elevational view of a dental reduce a certain amount of the shock of the burr according to thisinvention especially adapted burr against the tooth by decreasing the impact for use in straight handpieoes. v

pressures, and lessen the frictional heating of Figure 6 is an enlarged horizontal cross-secthe tooth. Likewise since the non-metallic vitional view taken along the line VI-VI of Figure bration dampener inserts are poor heat conduc- 4.

tors, heating of the handpiece during operation Figure 7 is an elevational View, with parts does not eiect heating of the burr. In ordinary broken away and with parts shown in rvertical cross-section, of a straight dental handpiece illustrating the manner in which the burr of Figure 5 is mounted therein.

Figure 8 is an enlarged vertical cross-sectional view of the chuck of a straight dental handpiece lined with vibration dampening material in accordance with this invention.

Figure 9 is an end view of the chuck taken along the line DI-IX of Figure 8.

Figure 10 is an elevational view of a contraangle dental handpiece with a part broken away and shown in vertical cross-section to illustrate the mounting of a burr such as shown in Figures 1 and 4 therein.

As shown on the drawings:

In Figures 1 and 2 the reference numeral I0 designates generally a drill or dental burr adapted for mounting in a contra-angle handpiece. The burr has a serrated cutting head I I and a shank I2 extending therefrom. In accordance with this invention, the upper end of the shank I2 which is to be mounted in the handpiece is reduced in diameter as at I3 and further reduced at the extremity thereof as at I4. A sleeve I5 of non-metallic vibration dampening material such, for example, as vulcanized rubber, molded plastic material, or the like, surrounds the reduced shank portions I3 and- I4 to 4cover the same. The sleeve I5 has an outer diameter the same as the normal diameter of the shank I2. The sleeve I5 has an annular groove I6 therein near the free end thereof and also has a iiat recessed portion I1. The groove I6 and the recessed portion I1 provide for the mounting of the burr in a contra-angle handpiece.

In Figures 3, 4 and 6, the reference numeral designates generally a modified form of dental burr in accordance with this invention. The burr 20 has a serrated cutting head 2| and a cylindrical shank 22 extending therefrom. In accordance with this invention, the shank 22 is formed in two parts each including a reduced, segmental cylindrical ringer 23 having a iiat face 24 along the length thereof. The finger 23 of the shank portion carrying the burr head 2| terminates short of the end of the burr shank. Likewise, the finger 23 on the other shank portion terminates short of the burr head. This other portion has a cylindrical end 25 overlapping the other nger 23 and is equipped with an annular groove 26 and a recessed portion 21.

The fingers 23 are mounted with their fiat faces 24 in opposed relation as best shown in Figure 6 and are bonded together by means of non-metallic vibration dampening material 28 such as vulcanized rubber, molded plastics or the like. The bonding material 28 also surrounds the fingers 23 to provide a sleeve 28a forming the exterior surface of the finished burr shank which extends from the lower end of the shank to the head 25. The bonding material 28 also extends over and under the ends of the ngers 23 as at 28e in Figure 4.

The resulting assembly therefore is composed of a metal burr head portion with a reduced longitudinally extending finger and a shank head portion with a similar reduced longitudinally extending finger. The iingers provide half-lap tabs and a non-metallic bonding material having vibration dampening properties unites the fingers to integrally join the burr head portion with the shank head portion while holding the portions in non-contacting relation. At the same time, the bonding material forms an enveloping sleeve along a major portion of the resulting shank of the burr.

As a result, vibration of the burr head 2| can only be imparted to the metal which is integral with the head and is then dampened out by the bonding material 28 from transmission to the head 25. The sleeve 28a iilters out the vibration through the contra-angle hand piece in which the burr may be mounted.

In the modification shown in Figure 5 the burr 30 has the usual serrated metal head 3l and the longitudinally extending metal shank portion 32. However, in accordance with this invention the shank 32 is reduced in diameter as at 32a, and is covered with a sleeve 33 of vibration dampening material such as vulcanized rubber, molded plastics or the like. The burr 30 has a cylindrical shank 32 which is somewhat longer than the shanks of the burrs shown in Figures 1 to 4 since the burr 30 is primarily adapted for mounting in a straight dental handpiece. The end of the shank, therefore, is not equipped with an annular groove or flat spot.

As shown in Figure 7, reference numeral 4D designates generally a straight dental handpiece of standard construction and mounted on swinging arm 4I of a dental unit. The handpiece 40 includes a tubular casing 42, a hollow body member 43 rotatably mounted in the casing 42 and projecting through the supporting arm 4I for receiving driving pulley 44 thereon. The driving unit is driven by the cord of the dental unit (not shown).

The body member 43 has a hollow tubular member 45 threaded thereon inside of the casing 42. The member 45 has a tapered end 45a. A wedge 46 is slidably mounted in the upper end of the member 45 and is adapted to be urged toward the tapered end 45a thereof by means of a pin 41 which extends through the body member 43 and is threaded through the end thereof as at 41a. The pin 41 projects through the body member above the pulley 44 and has a knurled knob 48 secured thereon for manual adjustment of the pin in its threaded seat.

The wedge member 46 acts upon a tubular chuck 49 mounted in the tapered end 45a of the member 45. The chuck 49 has slit tapered ends to be flexed inwardly by the tapered end of the wedge 4B and by the tapered portion 45a of the member 45. A burr such as the burr 30 has the sleeve covered shank portion 32a thereof inserted in the chuck 49 and the knob 43 is then turned to rotate the pin 41 for forcing the wedge 4S against the chuck thereby contracting the slit ends thereof and rmly holding the burr in the handpiece. Since the sleeve 33 of the burr is the only portion thereof which contacts any part of the handpiece, and since this sleeve is composed of non-metallic vibration dampening material, the vibration of the burr during the drilling of a tooth is not transmitted through the chuck to the dental unit.

This dampening or filtering out of vibration reduces shock and noise as explained above. The possible vibrating surface is greatly reduced and vibrations of the magnitude heretofore encountered are eliminated.

In accordance with a further modiiication of this invention the chuck 49 of the handpiece 4D can be lined with vibration dampening material as shown in Figures 8 and 9. As therein shown, a lining 50 is bonded to the interior of the chuck 49. This lining can be composed of any suitable vibration dampening material capable of exing with the metal of the chuck. The liner 50 can be used for direct engagement with regulation metal shanks of dental burrs or with sleeve covered shanks such as are shown in Figures 1 to 5.

As `shown in Figure 10, the reference numeral 5| designates a contra-angle handpiece adapted to be mounted on the end of the straight handpiece 40. The contra-angle member has a drive shaft 52 projecting from the end thereof adapted to be engaged by the chuck 49 of the straight handpiece. A bevel gear (not shown) is provided at the other end of the drive shaft for rotating a hollow receiving member or chuck for the contra-angle dental burr. This receiving member has a flat shoulder 54 at the upper end thereof adapted to engage the at spot on the contra-angle type burr. A retainer 55 is pivotally mounted on the contra-angle piece 5| for swinging into and out of engagement with the groove provided on contra-angle type burrs as pointed out above.

As shown in Figure 10, the burr lil has the shank thereof mounted in the housing 53, and the sleeve l5 around the shank is the only portion of the burr which contacts the contra-angle piece. As a result, Vibration of the burr head I I is dampened or ltered out to produce the results described above. Alternatively, the chuck or housing 53 can be lined with vibration dampening material.

From the above description, it will therefore be understood that this invention now provides for the insulation of metal burrs from metal to metal contact with a dental handpiece so that vibration of the burr head cannot be transmitted to the dental unit to the extent heretofore encountered. The invention provides for the dampening out of vibration either by lining the chuck of the dental handpiece with vibration dampening material or by covering the shank of the dental burr with such material, or both.

It will, of course, be understood that various details of construction may be varied through a wide range Without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims. For example while non-metallic dampener inserts are preferred, soft metal inserts such as lead could be used. Further, the specific illustrated burr heads are exemplary only since any type or shape of burr head can be used With the invention.

I claim as my invention:

l. A dental burr having a split half-lapped shank portion and a molded plastic separating member for said split shank position, said separating member having an outer wall embracing the lapped portions of said shank, a longitudinally extending wall within said outer wall and interposed between the opposed lapping surfaces of said split shank, and end walls between said longitudinally extending wall and the outer wall, said end walls being at opposite ends of said separating member and interposed between adjacent end walls of said split shank portions.

2. A split dental burr shank having sections provided with interlocking cooperating opposed surfaces of stepped formation conforming to the conguration of one another, said shank sections having a peripheral recess coextensive with the split portion of said shank, and a plastic locking member having a Wall seated in said peripheral recess and other walls interposed between said cooperating opposed surfaces whereby said sections are locked together for co-rotation and cushioned against each other.

MARTIN M. ELLMAN. 

